The present application claims priority to Swedish Application No. 0002662-5, filed Jul. 14, 2000.
1. Technical Field
The present invention relates to an assembly module having an airbag module and at least two modules for electrical operating controls, and a method for the assembly thereof.
2. Background Information
Modules for the assembly of crash cushions, commonly known as airbag modules, are already widely known, as disclosed in U.S. Pat. Nos. 5,755,458 or 5,149,127, for example. This type of module generally comprises a crash cushion fitted in a console, which is used in connection with the assembly of horn switches between the console and the steering wheel hub. One problem with such modules is that the electrical connections for the airbag module tend to protrude up through the steering wheel hub making them difficult to connect. There is also the risk of the wiring becoming trapped and damaged when assembling and dismantling the airbag module.
Another problem that occurs with this type of module is in obtaining the correct fit between steering wheel, airbag module and switch arrays for operating peripheral equipment. The switch arrays themselves may also be designed as modules, typically fitted directly to the steering wheel. This results in a poor fit between the modules and the airbag module. Further, the wiring for the modules is difficult to assemble and risks being damaged or trapped when assembling the airbag module. Since non-centered parts are unattractive, a customer may take a negative view of even very slight deviations. A precise fit is therefore desirable.
A further problem with the above assembly solution is that typically only the airbag module can be used for operation of the horn. In a stressful situation the driver must remember that the switch arrays do not have this function. Since the switch arrays generally extend from the steering wheel rim a distance onto the steering wheel spokes, the driver must take one hand entirely or partially off the steering wheel in order to be able to exert pressure on the airbag module.
The present invention provides an assembly module, that facilitates assembly and dismantling of the airbag module and modules for various operating controls, as well as simplifies the fitting between the various modules and between the assembly module and the steering wheel hub. This is achieved by an assembly module having a console that fits in a steering wheel hub of a steering wheel. The console may be provided with one or more notches for fastening an airbag module having a corresponding number of fastening elements. The console may also have fastening devices for one or more modules for electrical operating controls. These modules for operating controls may be either fastened to the console in connection with the airbag module, or detachably joined to the airbag module, or both. The airbag module and the modules for operating controls may have interacting first guides.
Normally, one operating control module, such as the car stereo system, telephone and navigation equipment, is fitted on each side of the airbag module. However, it is also possible to fit two such modules on each side, or, alternatively, one on each side and one at the bottom edge of the airbag module, depending on the design of the steering wheel hub and on the desired requirement for remote control of various electrical equipment from the steering wheel.
The modules for electrical operating controls are separately replaceable. Accordingly, it is easy to replace damaged modules or to upgrade one or more modules with further or new functions. The electrical connections can be connected either manually by joining the contacts together by hand when assembling, or automatically by automatically joining the module contacts together with corresponding connections when it is pushed into place when fitting to the console.
The airbag module is provided with a number of other guides that fit through the console for interacting with corresponding guides in the steering wheel hub. The guides also enable centering of the assembly module in relation to the steering wheel hub. The console is therefore flexibly mounted in the steering wheel hub in order to permit centering by the airbag module. The electrical connections of the airbag module can be made in the same way as the modules for operating controls.
The console also provides protection for electrical wiring in the steering wheel hub. By placing the console between the steering wheel hub and the airbag module and other modules, the risk of damaging wiring when fitting or removing the modules is minimized. If the connections for the modules are joined automatically by contacts that are pushed into one another, the length of the wiring can be minimized. In order to facilitate fitting and removal of the modules yet further, all fastenings may consist of snap fasteners.
One safety feature of the present invention is that all modules that are part of the assembly module are connected by way of the console to one or more horn switches in the steering wheel hub. As such, in a stressful situation the driver does not need to search for a particular button or press a specific part of the steering wheel such as the airbag module, since actuation of any part of the assembly module surface can activate the horn. It is important in this context to balance the force that is required for operation of the modules for other electrical equipment against the force required to activate the horn. Therefore, it must be possible to operate the switch arrays on any of the modules by applying significantly less pressure than is required for activation of the horn switch.
The invention also relates to a method for assembly of an assembly module as described above. The method comprises fastening a console in the steering wheel hub. At least two modules for operating controls provided with a number of guides are pushed into corresponding, interacting guide grooves in the console and fastened therein in conjunction with its fastening in the steering wheel hub. An airbag module provided with a number of further guides is pushed into corresponding, interacting guide grooves in the modules for operating controls, so that the modules are centered in relation to the airbag module, with the airbag module fastened in the console.
The modules for operating controls are fastened to the console after this has been fitted in the steering wheel hub, with the electrical connections automatically joined together. Alternatively, the operating controls modules may be fastened to the console before they are fitted in the steering wheel hub. This permits connection of the electrical connections before the console is fitted. In the same way the airbag module can be connected at the time of assembly by either automatic connection, or by manually joining together by way of an opening in the console that provides access to the leads situated behind. Preferably, the modules are replaceable without having to dismantle the console.
By means of the invention the operating control modules will be guided in correctly, and will provide a better fit and centering between the modules and the airbag module. Various parts of the assembly module may be dismantled in reverse order.